These continuation studies focus on large pancreas (PTx) and kidney (KTx) transplant populations of type 1 diabetic (D) patients (pts) in order to better understand diabetic nephropathy (DN), the leading cause of renal failure. Objectives are: (a) to determine whether PTx can more readily arrest or reverse the early vs. the more established lesions of DN; (b) to continue studies of renal structural-functional relationships in DN, with emphasis on the multifaceted pathologic DN lesions, including glomerular, vascular, interstitial lesions and glomerular-tubular connections; (c) to continue studies of DN natural history and the role of renal biopsy in predicting outcome; (d) to quantitate and understand the basis of atubular glomeruli (AG) in DN; (e) to elucidate glomerular (glom) epithelial cell abnormalities in DN; (f) to study the glom extracellular matrix abnormalities of DN; (g) to study the recurrence of DN in the KTx; (h) to study the molecular/genetic basis of DN and develop cellular markers of DN risk; (i) to determine the long-term (10-15 yr) structural consequences of cyclosporine (CSA) on the 'native kidneys of PTx recipients; and (j) to determine the shorter-term (5 yr) consequences of Prograf on the native kidneys of PTx recipients and compare these with those seen after 5 years of CSA treatment. Together, these studies will help to elucidate the pathogenesis and natural history of DN, unravel some of the molecular and genetic aspects of this disease, describe the dynamics of DN reversal in PTx pts, and recurrence in KTx pts and expand our knowledge of the nephrotoxic effects of calcinosis inhibitors.